The present invention relates to an illumination system of the digital control type for use in, e.g., a visual system of an industrial robot or the like.
Hitherto, visual systems for use in industrial robots use various kinds of methods such as indirect illumination, slit light projection, spot light projection, lattice pattern projection, and the like for the purposes of improvement of contrast between an object to be illuminated and the background, emphasis of edges of the object, detection of irregularity of the surface of object, and the like. However, according to those methods, each time the observation circumstances change, the intensity, position, direction, and pattern of the illumination, and the like must be manually or mechanically adjusted. Thus, there are the problems such that it takes a long time to adjust them and the reproducibility of the optimum illuminating conditions is very bad. Further, in the case of scanning a slight light or spot light, the use of mechanical movable parts such as a rotary mirror and the like are inevitable, so that there are the problems such that not only the scanning speed is limited but also the vibrations of the movable parts adversely influence on the scanning, and the like.